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By Mike Faure

Hercules cribs make use of timber loaded parallel and perpendicular to the grain. Maximum use is made of the orthotropic properties of timber resulting in crib- having superior strength, high initial stiffness and controlled post yield deformations. Blocks and timbers can be combined in many different ways resulting in thousands of different geometries. Each geometry has a specific combination of block on block, timber on timber and block on timber contact area which results in a unique performance. Each crib can be fingerprinted by defining four parameters relating to its load/deformation curve. If the geometry is known, the performance can be predicted with a high degree of accuracy. If the mine support requirements are known, the crib geometries can be designed which met theme requirements in the most cost effective manner Hercules cribs come closest to satisfying mine support requirements. Due to the flexibility of the concept and their superior strength, they can be employed in most mining situations to enhance safety, improve productivity, reduce working costs or improve profitability.

Jan 1, 1993

"With millions of dollars and thousands of lives at stake, the Iron Ore Company of Canada (IOC) turned to a private wireless network for help.IOC needed a network that possessed the ability to adapt to changes in a nanosecond and to function seamlessly in the most rugged of environments.Canada’s largest iron ore producer required a private wireless network powerful enough to support all mine applications and deliver all data to one central point — without any existing cellular/3G/Wi-Fi coverage.Operations at IOC, a leading global supplier of iron pellets, involved dispatch, drill management and equipment monitoring, pump control and remote video that must service three distinct pits. Due to its setup, the facility does not offer a great deal of flexibility for transmitting signals.IOC serves a robust customer base made up of North American, European and Asian steel producers. It also employs nearly 1,900 people. Catastrophic death and destruction are two very real potential consequences of system communication failure.Technology for tough terrainKinetic mesh technology was born in the wake of the 9/11 terrorist attacks on the United States, one of the most high-stakes emergency situations in U.S. history. The failure of the communications infrastructure on a massive scale that day underscored the need for networking technologies that could provide service even in the most chaotic of conditions.Kinetic mesh networks allow organizations to deploy networks at sites where communications infrastructure has been compromised, as well as quickly establish networks in places where they did not previously exist. Kinetic mesh networks have also demonstrated a better ability to adapt to network changes on-the-fly versus other types of networking technologies."

Jan 1, 2015

Cadmium occurs in the Broken Hill Lode essentially as a camouflaged element, substituting diadochically for zinc in the sphalerite.Analyses of a series of zinc concentrate flotation products, prepared from samples of ore taken at intervals throughout the developed lengths of the several orebodies forming the lode, have revealed a pattern in the distribution of cadmium relative to zinc. This pattern appears to reflect the temperature and order of deposition of the several orebodies, and the direction of movement of the mineralizing solutions.INTRODUCTIONThis investigation into the distribution of cadmium in the several orebodies of the Broken Hill lode was undertaken by the Mineragraphic Section. of C.S.I.R.O. in conjunction with the Broken Hill Geological Research Committee, as part of a study of Broken Hill mineralization.It arose from the examination of cadmium and zinc assays supplied by Mr. T. A. Read, Chief Metallurgist of the Broken Hill South Ltd.; of experimental zinc concentrates prepared from localized samples of the No, 2 and No. 3 orebodies in the Broken Hill South Mine. These assays suggested that the two orebodies were characterized by distinctive ZnjCd ratios.In view of the possible sigmficanc'e of such a difference, comparable data were sought from each of the other mines. The necessary samples of ore were collected by the geological staffs of the several mines. The preparation of separate zinc concentrates and lead concentrates from these samples, and their assaying, was conducted by Mr. Evan Hardy, for the North Broken Hill Mine, and its assodated leases, and by Mr. D., Swan, under the direction of Dr. J. C. Nixon, for the Zinc Corporation and New Broken Hill Consolidated Mines. Additional tests on the Broken Hill South Mine were made by Mr. C. W. Reilly, under the direction of Mr. T. A. Read. The samples were...

Jan 1, 1955

By N. Sano

The chromium oxide in stainless steel slags usually exists as Cr2O3. However, there is a possibility that it is oxidized to hazardous CrO3 after disposal or during use. Therefore, some technical developments to reduce chromium oxide by using a smelting reduction technique have been reported recently. This paper describes the fundamentals of the technique which have been applied to ferrochromium production and reviews the recent results in literature.

Jan 1, 2004

By Stephen T. Young

The construction of Phase 2 of Hong Kong Station, its retail podium and International Finance Centre Two, the tallest building in Hong Kong, will be completed in the middle of 2003. This paper describes the design and construction of the slurry wall for the Station (both Phase 1 and Phase 2) and the two commercial buildings at the Station. The slurry wall is used as the permanent earth support wall for the station box and the excavation depth ranges from 70 feet to 120 feet. Top-down construction technique was adopted to support the excavation of the station, while circular cofferdams relying on hoop stiffness were constructed to support the basement excavation of the two towers. The designed behavior of the slurry wall is also compared to the as built behavior.

Jan 1, 2003

By Lucas Breder Teixeira

Esse trabalho discute a modelagem termo-mecânica fisicamente não linear de materiais refratários considerando os efeitos de danificação utilizando o Método dos Elementos Finitos. Inicialmente é feita uma descrição geral dos materiais refratários com foco em suas características termo-mecânicas, destacando principalmente suas propriedades elásticas e comportamento de amolecimento, e demonstrando sua considerável dependência da temperatura. Algumas considerações são feitas com relação à evolução dos modelos de simulação numérica aplicados a refratários, iniciando-se com os modelos lineares elásticos até o uso de modelos constitutivos complexos. O modelo de fissuração distribuída utilizado para calcular a perda de rigidez elástica é então apresentado, juntamente com a fundamentação matemática pertinente e sua relação com os parâmetros físicos do material. Para ilustrar a aplicabilidade do modelo alguns exemplos são apresentados, discutindo-se suas principais capacidades com relação ao projeto de estruturas refratárias.

Oct 30, 2017

By Thomas M. Barczak

Roof support systems are necessary to provide stable mine openings and much research has been conducted to design a variety of roof support systems that will function in various manners to ensure that stable ground conditions are achieved. Despite these advancements in technology, mistakes continue to be made in the evaluation and/or installation that significantly degrade the support capability or lead to erroneous determinations of support expectations. The purpose of this paper is to discuss misconceptions about how roof supports perform and factors that impact their performance. The goal is to present practical information that will assist mine operators and engineers in selecting, installing, and evaluating roof support systems properly, and help them to avoid mistakes that can lead to erroneous expectations and potentially catastrophic results that may lead to roof falls. The paper is limited to a discussion of secondary roof support systems and powered roof supports such as longwall shields.

By M. Dobbins

The advent of the more efficient and effective rare-earth roll (RER) separator in the early 1980?s began a new era of dry magnetic separation. The RER units quickly became the separator of choice within the materials processing industry. Though RER separators are now commonplace throughout the world, only modest advancements have been made to the original design. This paper details recent, more significant, rare-earth magnetic separation developments. These developments maintain the best features of existing technology while minimizing shortcomings. The discussion includes discerning features that aid in better metallurgical performance. Also discussed are improved mechanical aspects that allow for both easier operation and maintenance. Performance details from various test programs are included.

Jan 1, 2009

By R. D. Yancich

A case study of longwall mining surface subsidence was performed at a mine in Southwestern Pennsylvania. The mine operated in the Pittsburgh coal seam which averaged 70-72 inches with 6-8 inches draw slate in the longwall location. The average overburden depth ranged from 625 8eet to 660 feet. Three adjacent longwall panels were studied and classified as Panel 1, Panel 2, and Panel 3. The following is information on each and can be seen on the General Mine Map (Fig. 1).

Jan 1, 1984

Significance of Ion Interactions in Flotation in Saline and Brine Solutions

Sep 13, 2010

By R. L. de Beauchamp

A preliminary investigation was made of the extraction of chromium from ferrochromium by low-temperature chlorination in the 3400 to 5250 C range. The objective was to devise a method for separating chromium from iron in high-carbon ferrochromium produced from domestic chromite concentrates. The majority of iron was removed as a volatile chloride; chromium was contained in the residue as a nonvolatile chloride, which was separated from carbon and unattacked ferrochromium by dissolution. A small rotary chlorination apparatus was designed, built, and used for the chlorination tests, and samples of commercial-grade high-and low-carbon ferrochromiums were chlorinated for comparison of chlorination characteristics. Low-temperature chlorination of three types of ferrochromium resulted in the removal of 81.9 to 91.6 percent of the iron content as sublimed FeC13. Recovery of chromium in a leach solution of the reactor product varied from 82.4 to 93.1 percent.

Jan 1, 1968

By David Jurich, Joseph N. McDivitt

INTRODUCTION South Coast Water District (SCWD) operates the Beach Interceptor Sewer Tunnel(BIST) in South Laguna, Orange County, California between Monarch Beach and Aliso Beach (Figure 1). The 10,200-foot long BIST houses a 24-inch gravity Techite sewer pipeline critical to the SCWD Sanitary Sewer Collection System. The original tunnel and sewer pipeline were constructed in 1954 and the sewer line was replaced in 1974.Periodic inspections by sewer pipeline maintenance crews documented deterioration of specific intervals of the tunnel. Rotting timber supports and rock falls in the tunnel as a result of the deterioration were endangering the sewer pipeline and a 731-foot section of tunnel located at Thousand Steps Beach was determined to be in immediate need of repairs. SCWD and consultants Hatch Mott MacDonald (HMM) and Tetra Tec prepared a Work Plan for emergency tunnel stabilization and pipe protection measures that was implemented in January 2007. Normal access to the beach and the section of tunnel requiring repairs was limited to public stairs referred to as Thousand Steps and, therefore, all materials and equipment needed for the work were transported to the beach by ocean-going landing craft. Additionally, the emergency repairs had to be completed without taking the pipeline out of service. Numerous environmental, logistical and operational requirements had to be overcome to complete the challenging emergency repairs. GEOLOGICAL SETTING The Laguna Beach area is located in the Peninsular Ranges of Southern California. The project area is located on the southwest flank of Niguel Hill along marine wave-cut cliffs and slopes. The tunnel was excavated in the San Onofre Formation, a marine deposit, characterized by abrupt lateral and vertical changes in lithologies that vary from boulder to cobble and gravel size breccias to medium coarse sandstones with gravel, sandy claystone and siltstone. The interval of the tunnel that required repairs is located within the San Onofre breccia, a moderately-to-well cemented, poorly bedded to massive unit with angular to subangular boulder and cobble sized clasts of schist. The sandy silt matrix of the breccia is composed of quartz, feldspar and schist grains (Figure 2). GENERAL TUNNEL DESCRIPTION The approximately 6-feet high by 6-feet wide 10,200-foot-long BIST was hand mined in 1954 at the base of the coastal cliffs. Primary access is through twenty-one access adits from public and private beaches. The tunnel is located in an easement that extends beneath private property with residential structures situated 50 to 80 feet above and horizontally in close proximity to the tunnel alignment. Most of the tunnel is horse-shoe shaped and unsupported, but approximately 3,000 feet is supported by timber

Jan 1, 2007

By K. Zenger, J. Kaartinen, J. Huuskonen, S. Torttila, S. Lähteenmäki, J. Pietilä

"Pyhäsalmi Mine in Finland has a long history of continuous process development. The concentrator processes Cu-Zn-sulphide ore with high recoveries. An on-line flotation simulator has been developed to maintain and further improve the flotation performance. Consisting of a flotation kinetic dynamic model, and interconnected with process control software, the simulator can be used for training new control room operators in various scenarios. For daily operation, the model parameters are continuously adapted to take into account the changing process conditions. On-line simulator tracking the process can provide the process operator new information in several ways: a) values of unmeasured process variables are obtained by displaying the corresponding simulator values, b) predictions of future process states and outputs are calculated and displayed, c) information of changing process parameters can be used as an indicator of e.g. change in the processed ore type. This paper describes the adaptive simulation system and its usage at the Pyhäsalmi concentrator.IntroductionPyhäsalmi massive sulphide orebody is located in central Finland. Operation of the mine started in 1962 and it is currently producing copper (Cu), zinc (Zn) and sulphur (S) concentrates. The concentrator control and optimization system has a long history of successful continuous development during the past decades (see e.g. Huuskonen & Moilanen, 2010). An on-stream analyzer has been a part of the automatic process control since 1968 (Lähteenmäki, Miettunen & Saloheimo, 1999). First control algorithms based on a flotation mathematical model were developed in 1971 (Koivistoinen & Miettunen, 1985). In 1990’s the development of a froth machine vision systems started (Kaartinen, 2009; Kaartinen, Roine & Hätönen, 2009). More recently Pyhäsalmi Mine Oy has been involved with several national development projects dealing with particle size distribution measurements (Kaartinen & Tolonen, 2008), spectral analysis of flotation slurries (Haavisto, Kaartinen & Hyötyniemi, 2008), and dynamic simulation of flotation processes. The latter topic is further elaborated in this paper."

Jan 1, 2015

By Flavio Rojos-Tapia, Samuel Sánchez-Pino, Marcelo Fernández-García, Samuel Sánchez-Baquedano, Rainer M. Imhof

"Pneumatic flotation was introduced to the Chilean copper mining industry in 1993 by Ingeniería de Minerales S.A., being implementation in 1994/95. The technology is based on the designs and development of Dr. Rainer Imhof from Germany and from Chilean copper processing experience.Pneumatic flotation has been successfully used for sulphide and oxide copper minerals and copper slag, iron ores (reverse flotation), gold and promising results with molybdenum as product. Extremely hard conditions were applied in flotation process such as roughing, cleaning, scavenging. Pneumatic flotation can be applied for any type of mineral which has to be separated by flotation. Even very dense and heavy slurries can be processed, the range of the particle sizes to be collected is very wide, and the number of cleaning stages needed normally is one in our experience until now.The good performance of the technique can be explained by the high gas hold-up and the very effective micro-turbulences which boosts the attachment to the bubbles changing dramatically the flotation time concept. Some economic high lights are: less energy consumption, less maintenance costs, simple and reliable to operate and it is required a small area to install the circuits.As a result of the Chilean mining industry experience, it can be concluded that the pneumatic flotation can be regarded as an excellent alternative to the conventional way of Mineral Processing.INTRODUCTIONDerived from seventies, works in Germany about pneumatic flotation with Prof. Simonis (Technical University of Berlin) and Prof. Bahr (Technical University of Clausthal), it has been developed an interesting flotation technology in Mineral Processing, with the designs developed by Dr. Rainer Imhof, who has been known for more than ten years (Imhof, 1998) by his contribution at Ekof, KHD, Allmineral and the actual company Maelgwyn Mineral Services where he is a Technical Director. Ingeniería de Minerales S.A. has been working ten years deeply involved with the technology developed by Dr. Imhof and is more than ten years experienced with pneumatic flotation, from Wits University and Mintek in South Africa (Sánchez, 1990), (Sánchez, 1990)."

Jan 1, 2003

By C. Laughton

Construction of a Deep Underground Science and Engineering Laboratory(DUSEL) is proposed under the auspices of the US National Science Foundation(NSF). DUSEL will provide scientists and engineers with a research facility capable of supporting a broad spectrum of fundamental and applied research deep in the earth’s crust. Research partners are physicists, biologists and geoscientists. DUSEL research calls for the construction of a network of shafts, tunnels and caverns that will provide laboratory facilities at depths of up to approximately 2 kilometers. The Project is still in the planning stages but, the initial experimental program is taking shape and conceptual designs have already been developed at two hard rock mine sites. This paper discusses the overall program and key engineering tasks being developed to support the construction of deep, large-span caverns. These caverns will house a new generation of physics experiments. As currently scoped, the experiments call for the excavation of permanent caverns with spans of up to 60 meters, sited at depths in excess of a kilometer.

Jan 1, 2007

By M. Mpofu, G. Stenzel, F. Magweregwede, B. Maphalala, T. Kgarume

Surface coal operations in which mining activities are conducted above old underground workings experience hot holes after drilling. In a coal mine, hot holes are defined as shot holes, which after being drilled have an in-hole ambient temperature of 40°C or above or show a temperature increase of 3°C or more during monitoring. Hot holes and other cavities, such as cracks, pose health and safety risks to workers, such as exposure to hot air and high concentrations of noxious gases released from these holes. In addition, workers may be exposed to premature detonation of explosives caused by in-hole temperature increases and chemical reactions. To this end, Coaltech Research Association commissioned a project to develop a Best Practice Guideline for the management of hot holes. This paper is a compilation of the activities conducted in the development of the Best Practice Guideline between 2021 and 2022. The activities included a review of standard operating procedures and hot-hole temperature-measuring and -monitoring devices, and the assessment of current hot-hole procedures at selected mines. The results indicated that management of hot holes requires a focus on pre-emptive risk assessment of mining blocks, identification of hot holes using the correct temperature-measuring devices, and continuous monitoring of hot holes from the time of drilling until just before blasting. Hot-hole management accessories, such as polyvinyl chloride sleeves, were found to be effective in insulating the hot-hole emulsion from the rock mass temperature, thus preventing the potential for premature detonation.

Sep 9, 2024

By Steve Kral

Reducing the cost per ton and increasing productivity are key factors in a mine’s profitability. Mining companies can do little about commodity prices. So to keep a mine operating at a profit, management must reduce costs and improve worker and equipment productivity in every facet of a mining operation. From mining to crushing to processing, mine management is constantly seeking new methods and technologies to improve the way it mines minerals. And it is willing to borrow techniques used by other operators.

Jan 1, 2002

By Cocquio D. S, Bauchau C

In the course of an integrated airborne survey in 1975, a uranium-molybdenum deposit was discovered by Minatome Australia Pty Limited in North Queensland, Australia, approximately 70 km by road west of Townsville.The mineralization occurs in a welded tuff unit within the Carboniferous St James Vokanics. It is structurally controlled by a complex of subvertical east-west fractures and is exposed over a strike length of 350 m. Drilling has traced a further 150 m extension underneath a barren capping consisting of a thick pile of vokano-sediments. The maximum width of the orebody is 150 m, and its vertical thickness is approximately 100 m.The primary ore minerals are coffinite, pitchblende and molybdenite, accompanied by various alteration products (particularly uranium molybdates).The vein-type mineralization is considered epigenetic.A comprehensive program of surface drilling and underground exploration is in progress to establish the uranium and molybdenum reserves.

Jan 1, 1980

By Alla D. Mah

The heat of formation of scandium sesquioxide (Sc203) has not been measured previously, and existing values for gallium sesquioxide (Ga203) are subject to large uncertainties. As a consequence, thermodynamic calculations involving these oxides hare lacked scientific exactness. This paper reports newly determined values of the heats of formation of gallium and scandium sesquioxides at 298.15° K., by combustion calorimetry. The corresponding free energies of formation are derived from heat and entropy data.

Jan 1, 1962

By L. E. Cardwell

This publication contains routine analyses and related source data for 377 natural gas samples from 19 States and two foreign countries. Of this total, 373 samples were collected during calendar year 1970. The remaining four samples were collected during previous years, but releases granting per-mission to publish the analyses were not received until 1970. All samples were collected as part of a continuous survey of the free world for occurrences of helium in natural gas. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4863 and 576.4 Twelve previous publications have presented the results of 9,050 gas analyses prior to 1970. The first three, Bulletins 486,6 576,8 and 617,7 contain analyses and related source data on 5,218 gas samples collected from

Jan 1, 1971